Things you might not know about the Data Perspective - Part 1 of many
jsayles 110000JV7B Comment (1) Visits (2177)
But you knew all that, right? Essentially, the Data Perspective is a much, much better SPUFI and QMF package for working with your DB2 assets - as an application developer and as a DBA.
But unlike SPUFI/QMF the Data Perspective does its DB2 access through a type 4 JDBC connection - saving considerable development CPU cycles versus SPUFI/QMF
And unlike SPUFI/QMF the Data Perspective work is both graphical in nature using wizards, and windows development techniques - so high-performance: http
Oh - you knew that too. I'm going to have to try harder to find something you don't know ... ah, how about this. So, from the Data Perspective:
Now what's in the SQL Results window? Aha - a list of all row values (now you know why I told you NOT to choose a Primary Key)
This is obviously useful to better understand your test data. And better, the OCCURENCE results column shows you a count of the number of rows that contain each value - AKA "cardinality" http
When you're designing your SQL for high-performance it's crucial to understand the role DB2 indexes play with your table access. If your SELECT statements often reference columns where certain values have low cardinality (perhaps the same value exists in > 20% of the table rows) if your host-variables contain that value you could be in for some heinous performance issues.
What can you do about this? A lot - most of which is beyond the scope of my little RDz blog - but it all starts with data analysis - and now you have an excellent and easy to use feature to work with.